Relation of kidney function and homocysteine in patients with hypothyroidism

OBJECTIVE: It has been found that both serum homocysteine (Hcy) and serum creatinine levels were increased in hypothyroidism patients. The aim of this study was to investigate the correlation between serum Hcy and kidney function in patients with subclinical hypothyroidism or hypothyroidism. METHODS: A total of 448 subjects were enrolled and divided into three groups: hypothyroidism (n = 129), subclinical hypothyroidism (n = 141), and control group (n = 168). Anthropometric information, metabolic parameters, serum Hcy and creatinine levels, and estimated glomerular filtration rate (eGFR) were analyzed. RESULTS: Compared with healthy subjects, patients with subclinical hypothyroidism or hypothyroidism had significantly higher serum Hcy and creatinine levels and lower eGFR level (all P < 0.001). Serum Hcy was negatively correlated with eGFR in subclinical hypothyroidism patients (r = −0.220, P = 0.009), and in hypothyroidism patients (r = −0.422, P < 0.001). After adjusting for age, sex and BMI, eGFR was still significantly correlated with serum Hcy in subclinical hypothyroidism or hypothyroidism patients (both P < 0.05). Levothyroxine treatment resulted in significantly decreased Hcy and increased eGFR in hypothyroidism patients (both P < 0.001). The decrease in Hcy was correlated with the increased eGFR after treatment (P = 0.001). CONCLUSION: Serum Hcy was negatively correlated with eGFR in subclinical hypothyroidism or hypothyroidism patients. After levothyroxine treatment, a correlation was found between the decrease in serum Hcy and the increase in eGFR in hypothyroidism patients.